1. Field of the Invention
The present invention relates to an apparatus and a method for pressure suppression and decontamination for a reactor container, and more particularly to an apparatus and a method for pressure suppression and decontamination for a reactor container which cools the inside of reactor container and suppresses the pressure rise and the density increase of radioactive substances, at an emergency case such as troubles with the coolant system for the reactor.
2. Description of the Background
When a severe trouble such as a trouble with a coolant system takes place in a nuclear reactor, it is possible that the reactor core melts, breaks through the bottom panel board of the reactor pressure vessel and falls into a bottom dry well. At that time, it is possible that a great amount of radioactive substances are generated and non-condensable gas such as hydrogen that is generated through reactions of metal and water fills up in the reactor container and causes a pressure rise in the reactor container. In the worst case, it is possible to exhaust a great amount of radioactive substances into outside air.
In order to take a countermeasure for such an event, it is investigated to install a cooling device for dry well either in a bottom dry well or in a top dry well and to cool the gas in the dry well or the cooling pool water for damaged reactor core. (Reference Patents 1 and 2 described below)
[Reference Patent 1] Japanese Patent Disclosure (Kokai) 2001-83275
[Reference Patent 2] Japanese Patent Disclosure (Kokai) 2001-215291
It is investigated to cool the dry well or the cooling pool water for the damaged reactor core at an emergency case such as troubles with the coolant system for the reactor, as described in the above. But the technology to suppress effectively the pressure rise in the reactor container and the density increase of the radioactive substances has not yet been developed.